Metal belt element, metal belt, and method of assembling the metal belt

ABSTRACT

A metal belt, comprising a metal band ( 18 ) passed around a drive pulley ( 12 ) and a driven pulley ( 15 ) and a plurality of elements ( 19 ) disposed laminatedly in the extending direction of the band; each element being formed of wire material and further comprising a body part ( 31 ) in contact with the pulley, vertically installed parts ( 32 ) erected from both sides of the body part, and a pair of hook parts ( 33 ) which extended from the vertically installed parts and disposed opposedly to each other, wherein an opening part ( 34 ) is formed with the body part and both hook parts and, because the band ( 18 ) is inserted into the opening part ( 34 ) of each element so as to prevent the element from falling down from the band, a falling prevention body ( 20 ) is disposed in the opening part overlappingly with the band ( 18 ).

BACKGROUND OF THE INVENTION

The present invention relates to an endless metallic belt to be extendedbetween a drive pulley and a driven pulley. The present invention alsorelates to an element constituting the metallic belt and a process ofassembling the same.

There is known a metallic belt used, for example, in an automotivestepless variable speed device, in which a multiplicity of slat-likeelements formed by punching a metal plate are layered to be slidablerelative to the longitudinal direction of the belt. In this metallicbelt, if the elements have corners, the corners of the elements candamage the band when they are brought into contact with it, beingcausative of breakage of the band.

However, since conventional metallic belt elements are very small andare formed by punching a plate material, it is impossible to subject theelements at the corners to chamfering or other treatments.

Also, since each element is made of a single plate material, the weightof the element cannot be reduced. These elements are circulated along acircular orbit over pulleys of a stepless variable speed device.However, if the element has a great mass, a great centrifugal force actsupon it accordingly. In addition, a great inertia force acts upon theelement when a vehicle is accelerated or decelerated. Such excessivecentrifugal force and inertia force reduce responsiveness and hindersmooth performance of the stepless variable speed device. Heavy elementscause these problems.

Further, since each element is made of a single plate, it hardly deformswhen an execessive load or force acts upon the element when contact withpulleys occurs. Thus an element cannot release the load or force, whichcauses damage or abnormal abrasion of the elements and pulleys.

The present invention was accomplished in view of the problems inherentin the prior art technique as described above. The object of the presentinvention is to provide a metallic belt element that can prevent damageand abnormal abrasion in such elements, bands and pulleys and that canoperate smoothly in power transmission, a metallic belt and a process ofassembling the metallic belt.

BRIEF SUMMARY OF THE INVENTION

In order to attain the above object, in metallic belt element accordingto a first embodiment of the present invention, the metallic beltelements are supported by an endless metallic band extended between adrive pulley and a driven pulley and are layered in the longitudinaldirection of the band. The periphery of the element is made of wire.

In a second embodiment of the present invention includes: a metallicbelt having an endless metallic band extending between a drive pulleyand a driven pulley; and a multiplicity of elements layered in thelongitudinal direction of the band. In the metallic belt, the peripheryof the element is formed of wire. The element includes a body, whichcontacts the pulleys, pillars, which rise from each side of the body,respectively, and a pair of hooked portions, which extends inward fromthe pillars and oppose each other. The body and the hooked portionsdefine an opening. A stopper is arranged on the band within the openingto prevent the elements from slipping off the band placed in theopening.

The third embodiment of the present invention is a suitable process ofassembling a metallic belt. According to this process, an endlessbelt-like stopper is located on the band. Next, the band is placed in anopening of each metallic belt element with the stopper being flexedlaterally. Subsequently, the stopper is returned to a normal planarstate to allow it to engage with inner side edges on both sides of theopening of each element, thus attaching the elements to the band.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side view showing the metallic belt according to a firstembodiment of the present invention;

FIG. 2 is a partially sectional side view of the metallic belt;

FIG. 3 is a vertical cross-sectional view of the metallic belt;

FIG. 4 is a front view of the element;

FIG. 5(a) is a plan view of the element;

FIG. 5(b) is a side view of the element;

FIG. 6 is a cross-sectional view of the wire;

FIG. 7 is a plan view of the stopper;

FIG. 8 is a plan view showing the state where the metallic elements arebeing incorporated into the band;

FIG. 9 is a side view showing the state where the metallic elements arebeing incorporated to the band;

FIG. 10 is a vertical cross-sectional view showing the state where themetallic elements are being incorporated into the band;

FIG. 11 is a plan view showing the state where the metallic elementshave been incorporated fully into the band;

FIG. 12 is a vertical cross-sectional view showing the state where themetallic elements have been incorporated fully into the band;

FIG. 13 is a side view showing the variable speed device according to asecond embodiment of the present invention;

FIG. 14 is a partial plan view of the metallic belt according to thesecond

FIG. 15 is a front view showing an element of the metallic belt shown inFIG. 14.

FIG. 16 is a side view showing the element of the metallic belt shown inFIG. 14.

FIG. 17 is a cross-sectional view of the wire;

FIG. 18 is a side view of the element according to a third embodiment;

FIG. 19 is a front view of the element according to the thirdembodiment;

FIG. 20 is a plan view of the element shown in FIG. 19;

FIG. 21 is a front view of the element according to a fourth embodiment,

FIG. 22 is a plan view of the element shown in FIG. 21;

FIG. 23 is a side view of the element shown in FIG. 21;

FIG. 24 is a front view of a prior art element; and

FIG. 25 is a front view of the prior art element.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present invention will be described below specifically by way ofembodiments realized in an automotive stepless variable speed devicereferring to the drawings.

First Embodiments

A first embodiment will be described in detail referring to FIGS. 1 to12. In the first embodiments, the expressions “upper” and “lower”, and“right” and “left” are referred to based on the drawing shown in FIGS. 2or 4. The expressions “ahead” and “behind” are also referred to based onFIGS. 2 or 4.

As shown in FIG. 1, a drive pulley 12 is attached to a drive shaft 11. Asubstantially V-shaped annular groove 13 is formed in the periphery ofthe pulley 12, as shown in FIG. 3. A driven pulley 15 is attached to adriven shaft 14, which corresponds to the drive shaft 11 in the drivepulley 12, and a substantially V-shaped annular groove 16 is formed inthe periphery of the pulley 15. An endless metallic belt 17 extendsbetween the two pulleys 12 and 15 and engages with the annular grooves13 and 16 to transmit rotation of the drive pulley 12 to the drivenpulley 15.

As shown in FIGS. 2 and 3, the metallic belt 17 is made essentially ofan endless metallic band 18, a multiplicity of metallic elements 19 andan endless belt-like metallic stopper 20, which is slightly wider thanthe band 18. The elements 19 are layered and are slidable relative toone another in the longitudinal direction to allow insertion of the band18 through them. The band 18 is formed by laminating a plurality ofmetal sheets and is subjected to surface treatment on both sides or onone side by sand blasting or shot peening. This surface treatmentpermits a lubricant to be carried to reduce frictional resistancebetween the band 18 and each element 19.

As shown in FIGS. 4 to 6, each element 19 is made by cutting a metallicwire 19 a, which has a circular cross section and which is formed bydrawing, into pieces of a predetermined length, bending the resultingpieces into the form of element 19, and pressing the resulting pieces.Each element 19 has a symmetrical form. The chain double-dashed lines inFIGS. 4 and 5(a) each show the shape of the element 19 before thepressing. Further, the entire outer surface of each element 19 istreated by sand blasting or shot peening like in the case of the band18. The surface treatment carries a lubricant to reduce frictionalresistance between the elements 19. Each element 19 has a hook-likepillar or rising portion 32 extending upward from each side of the upperface of a body 31. An opening or recess 30 is defined between thepillars 32 for receiving the band 18 and the stopper 20. The tips of thepillars 32 are bent inward to form engaging protrusions 33. An opening34, which is slightly wider than the band 18 and slightly narrower thanthe stopper 20, is defined between the engaging protrusions 33. Eachelement 19 is supported at the recess 30 by the band 18.

The shoulder 35 of the body 31 on which the band 18 is placed has anarcuate shape, which projects gently upward to prevent winding of theband 18. When an excessive downward load is applied to the body 31, theshoulder 35 flexes to have a gentler curvature (to be almost linear),which reduces stress.

A first slope 36 is formed on one side of each element 19 of the body 31by polishing. The first slope 36 is formed such that the thickness ofthe body 31 decreases gradually in the downward direction of FIGS. 4 and5(b). The first slope 36 allows the row of elements 19 to curve alongthe periphery of the pulleys 12 and 15 when engaged with them. The body31 has, on both ends, second slopes 37, which are inward slopes, in theview of FIG. 4. The second slopes 37 are formed by polishing. As shownin FIG. 3, the second slopes 37 are engaged with the inner side faces ofthe annular groove 13(16) of the pulley 12(15)

A boss 38 is formed by pressing at the center of the body 31, and adepression 39 is formed on the other side of the body 31 in alignmentwith the boss. Every two adjacent elements 19 engage with each other bythe boss 38 and the depression 39, and thus the elements 19 areconnected to one another in alignment.

As shown in FIG. 7, a plurality of slots 40 are defined in the stopper20. Also, small holes 40 a are defined adjacent to the slots 40. Whilethe slots 40 are defined in the stopper 20 in pairs at equal intervals,they may be continuous and formed all around the stopper 20. Further,the stopper 20 may have, on both side or on one side surface, surfacetreatment formed by means of sand blasting or shot peening, whichcarries a lubricant to reduce frictional resistance among the stopper20, the outermost layer of the band 18 and the elements 19.

The stopper 20 can be switched between a normal or a wide state, whichis shown in FIGS. 11 and 12, and a curved or narrow state, which isshown in FIGS. 8 and 10. The stopper 20 is fitted on the periphery ofthe band 18, and the width of the stopper 20 in the wide state of FIG. 7is then reduced to the narrow or flexed state shown in FIGS. 20 and 8 byengaging tools (not shown) with the small holes 40a to flex and reducethe width of the stopper 20. When the stopper 20 is in the curved state,it is designed to be slightly narrower than the width of the opening 34of the element 19. As shown in FIG. 9, the elements 19 are fitted to theband 18 through the opening 34 of each element 19 so that they aresupported by the band 18, and they are slid one after another toward awider portion of the band 18. When the elements 19 are all fitted to theband 18, the tools are disengaged from the stopper 20. The stopper 20then resumes the and flat state, and the ends of the element 19 engagethe engaging protrusions 33 respectively, as shown in FIGS. 11 and 12.In this state, the elements 19 are prevented from slipping off the band18.

Next, the effects of the above embodiment exhibits will be described.

In this embodiment, since each element 19 is provided with an opening 34having a suitable width with respect to the width of the band 18, theweight of the elements 19 is reduced, and the weight of the entiremetallic belt 17 is reduced. Actually, a 20 to 30% weight reduction wasachieved in the metallic belt. Since this reduces the inertia force, thebelt 17 is expected to show improved response to acceleration,deceleration and the like. Further, since each element 19 is made from adrawn wire, it is inexpensive. In addition, since each element 19 isobtained by subjecting wire, which has a circular cross section, topress molding, the elements 19 a do not have corners like those obtainedby punching a plate. Therefore, the elements 19 give no substantialdamage to the band 18 and the stopper 20, which improves the durabilityof the metallic belt 17. Since each element 19 has a pillar 32 on eachside, it is durable and resists from damage.

In the state where elements are supported by the band, it is necessaryto prevent the elements from slipping off the band, and measures havebeen proposed for this purpose. Japanese Unexamined Patent PublicationNo. Sho 55-100443 discloses a typical construction, as shown in FIG. 24.In FIG. 24, an element 301, which engages a band 300, includes a recess302 that opens laterally. In the apparatus shown in FIG. 24, the element301 includes a pair of recesses 302 that open laterally. JapaneseUnexamined Patent Publication No. Sho 62-35136 discloses an apparatus asshown in FIG. 25, in which, after a band 300 is placed in a recess 302of an element 301, a cross piece 304 is placed across the opening of therecess 302.

However, in the apparatus shown in FIG. 24, the element 301 may slip offthe belt 300 through the lateral opening. In the constitution shown inFIG. 25, the cross pieces 304 must be fixed to a multiplicity ofelements 301 by means of welding or the like, after the elements 301 areincorporated into the band 300. This is a difficult task, since theelements 301 are small. Besides, a cross piece 304 must be prepared foreach element 301. This increases the number of parts and makes theapparatus complicated.

In the first embodiment of the invention, the engaging protrusions 33 ofthe element 19 engage with the stopper 20 to securely prevent theelement 19 from slipping off. Incorporation of a single stopper 20 doesnot make the apparatus complicated compared with the prior art, forexample, as shown in FIG. 25, in which each element is provided with across piece 304 for presenting the elements from slipping off from theband.

Since the elements 19 are supported by the band 18 by using theflexibility of the stopper 20, they can be incorporated into the beltvery easily.

The slots 40 and small holes 40 a defined in the stopper 20 for flexingcontribute to reducing the weight of the metallic belt.

Second Embodiment

A second embodiment of the present invention will be describedspecifically referring to FIGS. 13 to 17. In the second embodiment, theexpressions “upper” and “lower”, and “right” “left” are based on thedrawing shown in FIG. 15. The expressions “ahead” and “behind” are alsobased on FIG. 15.

As shown in FIGS. 13 and 15, a drive pulley 112 is attached to a driveshaft 111. A substantially V-shaped annular groove 112 a is formed onthe periphery of the pulley 112. A driven pulley 114 is attached to adriven shaft 113, which corresponds to the drive shaft 111, of the drivepulley 112, and a substantially V-shaped annular groove 114 a is formedon the periphery of the pulley 114. An endless metallic belt 115 extendsbetween the drive pulley 112 and the driven pulley 114 to engage withthe annular grooves 112 a and 114 a to transmit rotation of the driveshaft 111 through the drive pulley 112, the metallic belt 115 and thedriven pulley 114 to the driven shaft 113.

As shown in FIGS. 14 and 15, the metallic belt 115 includes essentiallya pair of endless metallic bands 116 and a multiplicity of metallicelements 117. The elements 117 are layered between the bands 116 to beslidable relative to one another in the longitudinal direction of thebands 116.

Each band 116 is formed by laminating a plurality of endless belt-likebodies 118, each made of a metal sheet, and each endless belt-like body118 has surface treatment 118 a on both sides or on one side. Thesurface treatment 118 a is formed, for example, by a treatment orembossed pattern formed on the periphery of a roller, which is used whenthe endless belt-like body 118 is fed through a plurality of rollers.Otherwise, the surface treatment is formed by subjecting the endlessbelt-like body 118, which is rolled into a predetermined thickness, bysand blasting or shot peening to produce very small dimples, each havinga substantially arcuate cross section. Formation of the surfacetreatment 118 a reduces the contact surface area among the endlessbelt-like bodies 118 in each band 116 and between the band 116 and eachelement 117. The surface treatment also permits a lubricant to becarried in the dimples. Thus, frictional resistance among the endlessbelt-like bodies 118 and between the bands 16 and each element 117 isreduced.

As shown in FIGS. 14 to 17, each element 117 is obtained by bending ametallic wire 124, which has a substantially rectangular cross sectionand a predetermined length, to form an entire element 117. Each element117 has a symmetrical form. The elements 117 are obtained by cutting ametallic wire 124 into a predetermined lengths and bending the resultingpieces. Abutting portions, which are indicated by the chaindouble-dashed lines circles 150 in FIG. 15, are welded, Thus, emptyspaces S are defined in the wire 124.

The wire 124 is made of a ferrous metal such as a high carbon steel wirerod. Each element 117 has a surface treatment 117 a over its entireouter surface formed by sand blasting or shot peening. The surfacetreatment permits a lubricant to be carried to reduce frictionalresistance between the elements 117 and between the bands 116 and eachelement 117.

Each element 117 has a body 119 and heads 120 formed integrallytherewith through center pillars 121. The heads 120 extend from the body119 through the pillars 121. A pair of slits 125, in which the bands 116are inserted, is defined on one side of each pillar 121. The bands 116run through the slits 125, and the heads 120 prevents the elements 117from slipping off of the bands.

The shoulders 127 of the body 119 are located below the slits 125, onwhich the bands 116 are placed. Each shoulder 127 has an arcuate shapeand projects gently to prevent winding of the bands 116. The tips 128 ofthe heads 120, which are above the slits 125, are arcuately curvedupward, so that the tips 128 do not interfere with the surfaces of thebands 116.

A pair of first slopes 119 a are formed on one side of the body 119 oneach element 117. The first slopes 119 a are formed such that thethickness of the body 119 decreases gradually in the downward directionin FIG. 16. The body 119 in each element 117 also has, on both ends,second downward slopes 119 b. The second slopes 119 b are engaged withthe inner side faces of the annular grooves 112 a(114 a) of the pulley112(114). When the drive pulley 112 is rotated, the metallic belt 115 iscirculated to transmit rotation to the driven pulley 114. When the widthof the annular groove or grooves 112 a/114 a in one of or both of thepulleys 112 and 114 is changed due to a change in the torque of thedrive side or the driven side, the elements 117 shift in the radialdirections of the pulleys 112 and 114, accordingly.

A protrusion or boss 130 is formed at the center of the body 119. Theboss 130 has, on each side, tapered faces 130 a, which are widest at theupper end of the body 119 and which taper downward to be more narrowtoward the lower end of the body 119. Each boss 130 has on the rear sidea depression 131 conforming to the shape of the boss 130. Thus, thewidth of the boss 130 and that of the depression 131 change continuouslyalong the inner wall surfaces of the annular grooves 112 a and 114 a ofthe pulleys 112 and 114 to increase from the bottom of each groovetoward the opening. Every two adjacent elements 117 are engaged witheach other by the 130 and the depression 131 to prevent the elements 117from becoming misaligned.

As shown in FIG. 17, the wire 124 is arcuately chamfered at each of thefour corners 123. Thus, the element 117 has no comers on the peripherythat can damage the surfaces of the bands 116 and the inner surfaces ofthe annular grooves 112 a and 114 a of the pulleys 112 and 114.

The element 117 is obtained by cutting the wire 124, which has across-sectional profile as shown in FIG. 17, into a predeterminedlength, followed by bending. The ends of the wire 124 abut against oneanother at the pillars 121. The abutments may be mere abutment or may befixed by welding. The wire 124 is obtained by extrusion or cold rolling.Thus, arcuate chamfers are formed at the comers 123 simultaneously whenthe material 124 is extruded, and the thus molded wire 124 has a mirrorsurface.

Next, the effects of the second embodiment will be described below.

In this embodiment, each element 117 is formed by wire 124, so that thecomers 123 of the wire 124 can be chamfered easily when the material 124is extruded, as described above. The arcuately chamfered corners 123prevent damage to the bands 116 and pulleys 112 and 114, which improvesthe durability of the metallic belt 115.

Only the outer structure of each element 117 is formed by the wire 124,and empty spaces S are defined therein. This reduces the weight of eachelement 117 and of the metallic belt 115. Therefore, the centrifugalforce of the metallic belt around the peripheries of the pulleys 112 and114 and the inertia force in response to acceleration and decelerationis reduced, which results in excellent response and smooth performancein power transmission.

Since each element 117 is formed by the wire 124, each element 117flexes slightly inward when an excessive load or force acts upon it. Forexample, when an inward pressure is applied to the second slopes 119 bof each element 117 by the pulleys 112 and 114, the elements 117 flexslightly inward accordingly. This releases the load or force andprevents damage to or abnormal abrasion of the pulleys 112 and 114 andthe elements 117, which improves the durability of the metallic band115.

Since the wire 124 has substantially rectangular cross section, theelements 117 can be layered neatly in face to face contact with oneanother along the longitudinal direction of the bands 116, whichprevents vibration and noise and improves power transmission efficiency.

The entire periphery of each element 117 is composed not of faces formedby cutting but of faces formed by cold rolling. Therefore, even if eachelement 117 is subjected to sand blasting or other treatment, the flatsurfaces are merely roughened without marring the surface flatness. Thisensures surface contact between the elements 117 and contributes toefficient power transmission.

Since the shoulders 127 each have an arcuate shape, they prevent windingof the bands 116, preventing damage of the bands 116 and elements 117.

Since the tips of the heads 120 are arcuately curved upward, damage tothe tips 128 of the heads 120 and to the bands 116 is prevented.

Third Embodiment

A third embodiment will be described referring to FIGS. 18 to 20. Thethird embodiment is a modification of the second embodiment. The tips128 of the heads 120 in the third embodiment are curved forward.Therefore, in the third embodiment, the elements 117 can be maintainedin alignment by engagement between the tips 128 of every adjacent twoelements 117.

Fourth Embodiment

A fourth embodiment will be described referring to FIGS. 21 to 23. Thefourth embodiment is a modification of the first embodiment. A pair ofprotrusions 55 are formed on each side pressing in the fourthembodiment. The protrusions 55 are formed on each side of the body 31diagonally and symmetrically with respect to a plane Q including thecirculating face of the element 19. Each protrusion 55 has a fixed widthand a depression 56 formed on the rear side in alignment with theprotrusion 55.

If an excessive load is applied downward to the body 31, the shoulder 35flexes to have a gentler curvature (to be almost linear), which reducesstress.

Other Embodiments

For example, the shape of the element 19 in the first embodiment can bemodified variously. For example, through holes may be formed in the body31 reduce the weight.

While slots 40 and the like are formed in the stopper 20 of the firstembodiment, the shape of the slots 40 is not limited to that illustratedin FIG. 7, but various shapes may be used including a simple square anda rhombus.

In the first embodiment, the shape and the size of the boss 38 formed onthe body 31 are not limited as long as every adjacent two elements 19connect to each other without slipping off and the metallic belt 17 canmaintain its function. For example, the boss 38 may have a square crosssection. The shape of the depression 39 conforms to the shape of theboss 38.

In the first embodiment, the boss 38 and the depression 39 are formed onthe body 31. However, they may be formed on other portions, as long asevery adjacent two elements 19 are connected to each other withoutslipping off and the metallic belt 17 can maintain its function. Theymay be formed on the pillars 32. The connection between every adjacenttwo elements 19 may not depend on the engagement between the boss 38 andthe depression 39, and the lower end of the body 31 or tips of theengaging protrusions 33 may be curved depending on the direction ofconnecting the elements 19 to achieve engagement among the thus curvedportions.

In the first embodiment, the stopper 20 was bent when the elements 19were engaged with the band 18. However, it is also possible to orientthe element 19 diagonally with respect to the stopper 20 to bring oneside edge of the stopper 20 into the recess 30. Then, the element 19 isturned around that side end to place the band 18 in the recess 30.

In each element 117, abutting portions of the wire 124 may be welded atposition different from those illustrated in each embodiment.

In the third embodiment, the tips 128 of the heads 120 may be curved inthe opposite direction or backward in the view of FIG. 20.

The corners 123 of the wire 124 may be chamfered not arcuately butlinearly.

The empty spaces S defined in the elements formed by the wire 31 and 124respectively may be packed with a synthetic resin material forabsorption of vibrations, noises, etc.

Two or more kinds of metallic materials are provided for elements 19 and117, and these material are arranged or layered to be adjacent todifferent materials respectively. This constitution can reducevibrations, and noises due to the difference in the natural frequencybetween the adjacent elements 19(117).

Different materials from that employed in the above embodiments maybeused for the elements 19 and 117. There may be used, for example,ferrous metals other than hard steel and stainless steel.

The elements 19 and 117 may be subjected to surface hardening treatmentat the shoulders 35 and 127 of the body 31 and 119 and at the secondslopes 37 and 119 b in the elements 19 and 117.

A super hard metal power is sprayed over the shoulders 35 and 127 of thebody 31 and 119 and over the second slopes 37 and 119 b of the elements19 and 117, and the powder is melted by heating and solidified to form asuper hard alloy layer.

In the present invention, the element is formed using a wire. This canprevent damage of the bands and the like. Further, the weight of theelement can be reduced compared with the case where the element isformed using a plate material. In addition, if an excessive load orforce is acted upon the element, it can flex slightly accordingly torelease the load or force, preventing damage and abnormal abrasion ofpulleys and elements.

What is claimed is:
 1. A metallic belt element, a plurality of which areused to form a belt which includes an endless metal band for supportingthe elements, wherein the element comprises: a continuous piece of wirethat is bent into a predetermined shape, wherein the wire has a roundcross-section or a generally rectangular cross-section with roundedcomers, and wherein the shape includes a recess for receiving the metalband; wherein the element includes a body for engaging a pulley andpillars that extend from the body, wherein an arm extends from eachpillar in a generally lateral direction; wherein the element includes aprojection, which is located on a first side of the body, and adepression, which is located on a second side of the body, wherein thefirst side is opposite to the second side, and the projection conformsto the shape of the depression; wherein the first side of the body isformed such that the thickness of the body decreases gradually in thedownward direction.
 2. A metallic belt element, a plurality of which areused to form a belt which includes an endless metal band for supportingthe elements, wherein the element comprises: a continuous piece of wirethat is bent into a predetermined shape and is then pressed, wherein thewire has a round cross-section or a generally rectangular cross-sectionwith rounded corners, and wherein the shape includes a recess forreceiving the metal band and a stopper to prevent the element fromslipping off the band; wherein the element includes a body for engaginga pulley and a pair of pillars that extend from the body to risegradually outward, wherein an arm extends from each pillar in agenerally lateral direction; wherein the element includes a projection,which is located on a first side of the body, and a depression, which islocated on a second side of the body, wherein the first side is oppositeto the second side, and the projection conforms to the shape of thedepression; and wherein the first side of the body is formed such thatthe thickness of the body decreases gradually in the outward direction.3. The metallic belt element according to claim 2 wherein the projectionis circular in cross-section.
 4. The metallic belt element according toclaim 2 wherein the stopper is of a thin plate and contains throughholes, which are designed to reduce rigidity of the stopper and toimpart flexibility thereto.
 5. The metallic belt element according toclaim 2, wherein the element has a plane of symmetry, and the projectionextends in an oblique direction to the plane of symmetry.
 6. An endlessmetallic belt comprising an endless metal band for supporting aplurality of elements; a plurality of elements disposed on said endlessmetal band; and a stopper disposed on said endless metal band to preventthe elements from slipping off the band, wherein each said elementcomprises: a continuous piece of wire that is bent into a predeterminedshape and is then pressed, wherein the wire has a round cross section ora generally rectangular cross-section section with rounded corners, andwherein the shape includes a recess for receiving the metal band and thestopper, the element including a body for engaging a pulley and a pairof pillars that extend from the body to rise gradually outward, whereinan arm extends from each said pillar in a generally lateral direction,the element further including a projection, which is located on a firstside of the body, and a depression, which is located on a second side ofthe body, wherein the first side is opposite to the second side, and theprojection conforms to the shape of the depression, the first side ofthe body being formed such that the thickness of the body decreasesgradually in the outward direction.
 7. A metallic belt element, aplurality of which are used to form a belt which includes an endlessmetal band for supporting the elements, wherein the element comprises: acontinuous piece of wire that is bent into a predetermined shape,wherein the wire has a round cross-section or a generally rectangularcross-section with rounded corners, and wherein the shape includes arecess for receiving the metal band, wherein the recess is a firstrecess for receiving a first belt, and the element includes a secondrecess for receiving a second belt; wherein the element includes a bodyfor engaging a pulley and a pillar that extends from the body, wherein apair of arms extend from the pillar in a generally lateral direction;wherein the element includes a projection, which is located on a firstside of the body, and a depression, which is located on a second side ofthe body, wherein the first side is opposite to the second side, and theprojection conforms to the shape of the depression; and wherein thefirst side of the body is formed such that the thickness of the bodydecreases gradually in the outward direction.
 8. The metallic beltelement according to claim 7, wherein the first recess is a mirror imageof the second recess.
 9. The metallic belt element according to claim 8,wherein the first recess and the second recess are defined between thepair of the arms and the body.
 10. The metallic belt element accordingto claim 7, wherein the element has a plane of symmetry, and theprojection has tapered faces that extend in an oblique direction to theplane of symmetry.
 11. An endless metallic belt comprising a pluralityof metallic belt elements; and an endless metal band for supporting theelements, the metal band including a first belt and a second belt,wherein each said element comprises: a continuous piece of wire that isbent into a predetermined shape, wherein the wire has a round crosssection or a generally rectangular cross-section with rounded corners,and wherein the shape includes a recess for receiving the metal band,wherein the recess is a first recess for receiving the first belt, andthe element includes a second recess for receiving the second belt;wherein the element includes a body for engaging a pulley and a pillarthat extends from the body, wherein a pair of arms extend from thepillar in a generally lateral direction; wherein the element includes aprojection, which is located on a first side of the body, and adepression, which is located on a second side of the body, wherein thefirst side is opposite to the second side, and the projection conformsto the shape of the depression; wherein the first side of the body isformed such that the thickness of the body decreases gradually in theoutward direction.